This invention relates to units for generating a predetermined gaseous atmosphere in a closed container and/or for indicating the presence or absence of the predetermined atmosphere in the container. More particularly, the invention relates to generating and/or indicating units for use by the medical profession in collecting, transporting and storing bacterial cultures of the type which remain viable only when in the presence of a particular gaseous environment or atmosphere. For example, bacteria of the anaerobic type require an oxygen-deficient or oxygen-free atmosphere and should be transported and stored in an environment having little or no oxygen.
Units used for somewhat the same general purposes as the units of the present invention are disclosed in Brewer U.S. Pat. Nos. 3,246,959 and 4,287,306; Spinner et al U.S. Pat. No. 4,013,422 and 4,023,934; Rosiere U.S. Pat. No. 4,012,203 and Johnson U.S. Pat. No. 4,377,554. The Spinner et al '422 patent discloses a gas generating unit for creating an anaerobic atmosphere in a flexible bag while the Spinner et al '934 patent discloses an indicator unit for visually signaling whether the anaerobic atmosphere is present or absent in the bag. In each unit, a sealed ampoule containing a liquid is disposed in a tube adapted to be inserted in the bag. When the ampoule of the gas generating unit is broken by squeezing the bag and the tube, the liquid in the ampoule is released and activates a gas generating material to create a flow of gas out of the tube and into the bag. When the ampoule of the indicator unit is broken, the released liquid soaks an absorbent material which assumes different colors depending upon whether the gas flowing into the indicator tube from the bag is aerobic or anaerobic. In this way, medical personnel can both create an anaerobic atmosphere in the bag and can visually determine whether or not the integrity of such atmosphere has been maintained over the required period of time.